This invention relates to the removal or recovery of oil, fuel layer, or other hydrocarbons or pollutants from the surface of water or other fluids of higher density than the material on the surface.
Many groundwater remediation techniques use an slurp tube to remove the free product on the surface of water of, for example, a well. A typical slurp tube has a pipe with an open end nozzle at the bottom end which can be lowered into a well to extract the free product. The slurp tube must be manually adjusted to lift and lower the pipe to maintain the level of the open end nozzle approximately at the top 1/4" of the water just below the free product. The bottom end design of the nozzle results in a large amount of water entering the nozzle.
Some have employed a flexible line that is towed with boats along the surface of the water to extract oil or other free product on the surface of the water, such as that disclosed in U.S. Pat. No. 4,133,765 to Stupica. The flexible tube may cause a clog inside when it is bent, and must be made of a soft material that may be damaged by repeated bending.
Other techniques employ the principle of neutral buoyancy in which an apparatus has a flexible tube supported by a float, such as those shown in U.S. Pat. Nos. 4,663,037 and 5,474,685 to Breslin. The tube has an upper inlet disposed near the oil layer. A portion of the flexible tube moves with the float while the remaining portion of the flexible tube is fixed. The apparatus operates as a perfectly balanced scale. The slightest load change, which may be caused by a shift in weight of the tube as it moves with the float, will change the balance. As a result, the apparatus will either float on the surface of the oil or sink due to the loss of balance.